zobel circuits necessary?

So I was looking at building new crossovers as I'm going to change speaker impedances, so I kind of have to. Anyway, this go around I'm going to keep them simpler (2nd order, not 4th) but use better parts. So, each feature I add is going to add a lot more cost this time. My old ones had zobel circuits for the 7" woofers. Will I really notice the difference? Since they need some fairly large value caps to make them, it'll add something like $20-$40 in cost to the new crossovers. I'm really wondering if I should bother. Also, when I make the L-pads for the tweeters, what amount of attenuation should I be shooting for? This isn't my car, but same model, so this is what the speaker layout looks like (Tweeters are on the top section of the door panels. No, I can't move them closer to the woofers, would require a ton of custom work.) I think the last time I discussed this, someone suggested about 3db quieter than the woofers. Should I go for this? Problem is, if I end up not matching the levels right the first time, I have to wait on ordering a new pair of resistors to try some more settings, and then pop open the x-overs and re-solder them. So I'd like to get it right the first time.'96 Mazda Miata